Shimano Ultegra Di2 ST-R8170 BR-R8170 Hose Rear Disc Brake Kit.

• Clean cockpit: the wireless connection improves the aerodynamic effect and facilitates maintenance.
• Unmatched ergonomics, perfected with professional feedback.
• The raised handguard improves ergonomics.
• Optimized brake control.
• Lighter, smoother lever action.
• Optimized modulation thanks to a larger braking control area.
• Compatible with wired and wireless connection.
• Available for additional satellite shift controls.
• High electronic energy efficiency.
• 1.5 to 2 years of battery life with easy-to-replace CR1632 shifting shifter batteries.
• Pad clearance increased by 10% reduces brake noise.
• Low maintenance purge procedure.